Solutions articles that are exact duplicates of docs pages

[SimonWoolf]

Just discovered https://www.ably.io/documentation/general/channel-rules-namespaces , which contains essentially the same content as https://support.ably.io/support/solutions/articles/3000030058-what-is-a-channel-namespace-and-how-can-i-use-them- .

Well... almost the same content. The solutions article was updated when we added push notifications as a namespace setting. The docs page wasn't. This is the issue with duplication - whoever updated the solutions article likely made the reasonable assumption that they had found the place that listed namespace settings, and stopped looking, so the other page didn't get updated.

I think we should delete one of them.

┆Issue is synchronized with this Jira Bug by Unito